Fluoride‐Engineered Electrolyte for Highly Stable and Efficient Alkaline Seawater Electrolysis at 2 A cm <sup>−2</sup>
Jingjin Cheng, Wei Liu, Sirui Chen, Yu Zhang, Aiqing Cao, Yixin Zhang, Zexiang Shen, Yongqiang Yang, Yaling Zhang, Yaping Li, Daojin Zhou, Xiaoming Sun
Abstract
Abstract Seawater electrolysis offers an energy‐efficient route for hydrogen production while alleviating freshwater scarcity. However, the presence of Cl − in seawater compromises anode activity and induces severe corrosion, requiring constructing complex electrode architectures that hinder large‐scale application. In this work, we demonstrate that incorporating F − as an electrolyte additive significantly enhances the performance of NiFe layered double hydroxide (NiFe‐LDH) anodes. Upon optimizing the F − concentration, benchmark NiFe‐LDH showed the lower overpotential than that of the F − ‐free system, and achieved stable operation at 2 A cm −2 for 1000 h in seawater electrolyte, representing an approximately 500‐fold improvement over the control set of experiment. The consistency between spectroscopic characterization and multi‐scale simulation results revealed that F − , by virtue of its high electronegativity and charge density, modulates the electronic environment of Ni and Fe sites, enhances the adsorption of OH − , and thereby improves OER activity. Moreover, the introduction of F − increases free water content and modulates the hydrogen bond network to promote OH − transportation while repelling Cl − at the electrode‐electrolyte interface by polarizing the O─H bonds of water molecules on NiFe‐LDH surface. This straightforward electrolyte engineering strategy provides a practical and scalable solution for seawater electrolysis.